1. Field of the Invention
This invention relates to aqueous cosmetic hair treatment preparations containing an alkylether sulfonate anionic surfactant and preferably having an acidic pH value.
2. Statement of Related Art
Many aqueous hair treatment preparations contain surfactants to obtain better wetting of the hair, emulsification or dispersion of water-soluble components, more uniform distribution of the components on the hair, or to obtain a foaming and washing effect. Among the surfactants used, anionic surfactants are the most important by virtue of their good foaming and washing power and their good wetting and dispersing action. Alkylether sulfates in particular have acquired considerable significance by virtue of these favorable performance properties and because they can be heavily thickened, even in dilute aqueous solution, by addition of electrolytes. However, they are attended by the disadvantage that they undergo hydrolysis during prolonged storage, particularly at pH values below 5, by a reaction which is autocatalytically accelerated once it has started through the formation of sulfuric acid. Known hydrolysis-stable surfactants, for example nonionic ethylene oxide adducts, are not sufficiently foam-forming; others, for example the anionic alkylbenzene sulfonates, are not sufficiently compatible with the skin for cosmetic applications and yet others, for example the alkane sulfonates and .alpha.-olefin sulfonates, cannot be sufficiently thickened with electrolytes in aqueous solution, which is a disadvantage where they are to be used for example in shampoos.
Accordingly, there is a particular need for cosmetic hair treatment preparations which contain an hydrolysis-stable surfactant having favorable performance properties, particularly foam power, compatibility with the skin and thickenability in aqueous solution.